The role of MiR-361-5p in delayed fracture healing and its clinical predictive value

Abstract Objectives Delayed fracture healing (DFH) is a common clinical complication in orthopedic trauma. This study aims to investigate the expression patterns and regulatory mechanisms of miR-361-5p in DFH. Methods Patients with normal fracture healing (NFH) and DFH were included in this study. miR-361-5p levels in the subjects were detected using RT-qPCR, and the predictive value of miR-361-5p for DFH was evaluated through Receiver Operating Characteristic (ROC) curve. MC3T3-E1 cells were induced to undergo osteogenic differentiation in vitro , and the functional role of miR-361-5p in this process was investigated. The expression levels of osteogenic differentiation markers, including alkaline phosphatase (ALP), osteocalcin (OCN), osteopontin (OPN), and runt-related transcription factor 2 (RUNX2), in the cells were quantitatively assessed using RT-qPCR. Dual luciferase reporter assay and RNA immunoprecipitation assay were used to verify the targeted binding relationship between miR-361-5p and FGF7. Results miR-361-5p significantly increased in patients with DFH. Serum miR-361-5p had a sensitivity of 87.93 % and a specificity of 74.14 % for the prediction of DFH. During the process of osteogenic induction, we observed that the expression level of miR-361-5p gradually decreased. And this molecule is negatively correlated with the level of osteogenic markers. We found that miR-361-5p directly targets FGF7. Transfection with miR-361-5p inhibitor can enhance the activity of ALP and increase the levels of osteogenic markers. However, specific inhibition of FGF7 partially counteracted these effects. Conclusions MiR-361-5p can be used as a potential predictor of DFH. miR-361-5p inhibits osteogenic differentiation by targeting FGF7, thereby delaying the process of fracture healing.